The present invention relates to preparation of terminal portions of multi-conductor electrical cables and connection of the conductors of the terminal portions of such cables electrically to respective portions of electrical circuits, and in particular the present invention relates to terminal portions of cables including a large number of coaxial conductor pairs.
Multiple conductors often need to be installed and connected electrically with a portion of an electrical circuit at a predetermined spacing and to be terminated at a predetermined length for each conductor. The conductors may be single insulated conductors, or coaxial conductors, hereinafter referred to as coaxial conductor pairs, typically including a central conductor and a surrounding shield conductor. In some cases there may be additional coaxially located conductors, and the term coaxial pair is intended herein to include such conductors as well. Since terminal preparation work on individual conductors may be done at a location remote from the place where conductors are finally connected into an electronic circuit, the task of installing a large number of conductors individually in the proper places can be very time-consuming. Manually identifying and positioning conductors, shields, and non-conductive elements such as dielectric layers and jackets one by one during final installation of conductors thus makes the task of installing multi-conductor cables very tedious.
It is necessary to protect terminal portions of conductors from damage during transportation from the point of preparation to the location where final installation is to be carried out, and it is usually necessary to maintain proper identification of individual conductors, as when one end of a set of conductors, such as those included in a multi-conductor cable, is already connected to a multi-conductor connection device which fixed the identification of each conductor. The opposite terminal portions of such conductors have to be identified, prepared and connected into an electrical circuit in locations which depend on the arrangement of terminals in that electrical circuit, but which may involve entirely different groupings of the several conductors.
Furthermore, it is often necessary to test individual conductors or coaxial conductor pairs of a multi-conductor cable to be sure that they all meet specifications for various characteristics such as impedance, capacitance, signal transmission velocity, or cross-talk. It is undesirably time-consuming and often difficult or tedious to accomplish connection of test devices to conductors individually, particularly when the conductors are of extremely small size, when those conductors are not restrained against freedom of movement.
Additionally, it is sometimes desirable to achieve connection of the conductors or coaxial conductor pairs of multi-conductor cables with a portion of an electrical circuit in a space smaller than that which would be required if each of the conductors were attached through the use of a terminal connector attached to the cable and mating with a corresponding connector attached to the electrical circuit.
It has previously been suggested that improved speed of termination of groups of conductors from a multi-conductor cable can be accomplished using a device such as a supporting frame of thin metal to which each of the conductors may be mechanically attached, as by solder, to leave the conductors exposed within an opening defined by the frame so that they can be soldered appropriately into electrical connection with terminal pads and ground plane contacts located in a predetermined array, as on a printed circuit board or the like. The frame would include registration devices to keep it in the required position while the conductors are being connected. Such a frame, however, since it is conductive, would make it impossible to test capacitance, impedance, and other characteristics of the several conductors individually, and the thermal conductivity of such a metal frame would make it difficult to unsolder and replace individual conductors on such a frame if that should be necessary.
What is desired, then, is apparatus and a method through whose use it is possible to reduce the amount of time and manual labor needed to achieve electrical connection of many separate conductors or coaxial conductor pairs into an electrical circuit in specific positions, at a location remote from the manufacture and assembly of the conductors.
It is also desired to have apparatus and a method for its use in accomplishing separate testing and selective replacement of multiple conductors, such as those of a cable, more quickly than has previously been possible.
And finally, what is also desired is that the many conductors as prepared and held in a desired layout be preserved in this position temporarily so as to make removal from production fixtures and transportation to a remote site for termination possible.